[Xen-changelog] [xen-unstable] arm: add bounds check on hypercall array

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1343234361 -3600
# Node ID a1ee7eccd83e533785aa35caa49833a1277807d3
# Parent  7118869c9cbee6d8bd850aa58ebec00e6486fb16
arm: add bounds check on hypercall array

Otherwise a guest can cause us to run off the end of the array.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
[ ijc -- switched to >= not > ]
Committed-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---


diff -r 7118869c9cbe -r a1ee7eccd83e xen/arch/arm/traps.c
--- a/xen/arch/arm/traps.c      Wed Jul 25 17:39:20 2012 +0100
+++ b/xen/arch/arm/traps.c      Wed Jul 25 17:39:21 2012 +0100
@@ -479,6 +479,12 @@ static void do_trap_hypercall(struct cpu
         return;
     }
 
+    if ( regs->r12 >= ARRAY_SIZE(arm_hypercall_table) )
+    {
+        regs->r0 = -ENOSYS;
+        return;
+    }
+
     call = arm_hypercall_table[regs->r12].fn;
     if ( call == NULL )
     {

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